Pitting corrosion identification approach based on inverse finite element method for marine structure applications

Abstract

This paper presents a state-of-the art inverse finite element method (iFEM) for full-field, real-time structural health monitoring (SHM) of corroding structures. The study focuses on detecting the location and identifying the extent of pitting corrosion, which is one of the most hazardous forms of corrosion due to the difficulties regarding its prediction and detection. For this purpose, high-fidelity finite element (FE) models of corroded samples with complex-shaped, semi-ellipsoidal, and cylindroconical defects are developed to replicate the strain field of pitting corroded structures. The strain fields produced by the FE models, verified against experimental data, are reconstructed by the iFEM model using a robust and practical four-node quadrilateral inverse-shell element, iQS4. A strain-based damage criterion is defined to obtain the damage distribution and the location of corrosion pits on dog-bone tensile test samples with full sensor iFEM and coupled iFEM-GA reduced sensor technique. Finally, in a practical example of a structure with complex geometry, the proposed method's performance is assessed through detecting the location of corrosion damage on a cylindrical marine structure with axial stiffeners.